i will burn for the things i love
by splendidlyimperfect
Summary: Natsu eats some unfamiliar flames and ends up out of control. Gray's the only one who can save him.
1. Chapter 1

_A/N: This is an "alternate version" of the scene in 100-Year-Quest when they fight Mercuphobia and {spoilers} Ignia shows up to set everything on fire. You don't need to have read it for this to make sense, though! _

* * *

Everything was on fire.

To be fair, that wasn't anything new. Quests with Natsu generally ended with _something _up in flames, and as much as Gray hated to admit it, it was usually effective. But this was something entirely different.

This time, Natsu was out of control, and Gray didn't know how to stop him.

"What's going on?" Lucy shouted, backing away from the flames that roared around Natsu. The water god dragon's enormous body lay at Natsu's feet, stretching through the blackened ruins of the village. "We got him, why's Natsu still…" Lucy trailed off, gesturing at Natsu's strange form. "…like that?"

Gray didn't answer – all he could do was stare. A cold, uncomfortable feeling crept through him as he stared at Natsu's sharp teeth and bright scales and dark claws. He looked monstrous; an unholy dragon with eyes like a demon.

_Natsu, _Gray thought desperately, swallowing down the fear that was turning to bile in his stomach. _Come back. Please don't make me fight you again. _

They both had scars from their last battle – scars that were still healing the first time Natsu had kissed Gray.

"I've never seen him like this," Erza shouted, raising her arm to protect her face from the ash that flew through the air around them. Tiny sparks jumped from Natsu's flaming form, hitting the ground and flaring up again before dissipating. "He doesn't even recognize us."

"It was that… whoever he was talking to," Gray said, staring up at the sky where the person – dragon? – had disappeared. It had looked like Igneel at first, but that was impossible. Gray had held Natsu after Igneel died; they had cried together, collapsing with the exhaustion of loss and grief. Igneel was gone.

But a dragon _had _appeared, and Natsu had eaten its flames, and now something was very, very wrong.

Another burst of flame erupted from Natsu as he tipped his head back and roared at the sky. Gray barely had time to throw up an ice barrier between Natsu and the rest of the group, and it melted almost immediately.

"You guys have to go," Gray said, turning to the group. "I'm the only one that can get close to him, I'll try to talk him down."

"He's too strong, you're going to get hurt." Wendy's eyes were wide as she stared over Gray's shoulder. "We should—"

"I can stop him," Gray interrupted, shaking his head. "Get out of here." Erza looked like she was going to argue, but Gray shook his head. "He'd never forgive himself if he hurt you guys," he insisted.

_And I don't want you watching if I have to hurt him, _he thought.

"Gray's right," Erza said eventually. "At this rate he's going to burn down the whole city." She grabbed Gray's hand and squeezed it gently. "Be careful," she said, before taking Lucy and Wendy's arms and guiding them away.

Gray waited until they were a safe distance away before turning back to face Natsu. Tornadoes of flame were raging out of control around him, burning through buildings like kindling and leaving only ash in their wake.

Black, inky tendrils crawled across Gray's skin, reacting to the darkness in Natsu's eyes. Gray squeezed his eyes shut, forcing the marks away.

Natsu wasn't a demon, and Gray wasn't going to slay him.

"Natsu!" Gray shouted as he stepped forward. The heat pulsing from Natsu was even more intense than the flames had been before – Gray could feel his skin blistering even through the thick layer of ice he'd surrounded himself with. "Natsu, stop it! Look at me, you're gonna hurt someone!"

Natsu just snarled at him – a guttural, inhuman sound that made Gray's teeth hurt. Natsu's eyes were dark and wild, fingertips stained with a strange darkness that slowly crept up his forearms. He looked unholy in the midst of the inferno – flickering light reflecting off his dark skin.

"C'mon, love," Gray said gently, taking another step forward. Natsu snarled at him, sharp teeth flashing against the flames around them. His scales were spreading, further than Gray had ever seen them before – Natsu was almost completely covered in shards of iridescent red and orange.

If it wasn't so destructive, Gray would have found it beautiful.

The heat around him intensified and Gray winced, putting both arms up in front of his face to shield himself. His heart pounded, sweat trickling down the back of his neck, ice around him melting quicker than he could create it.

"Have to burn it," Natsu rasped as flames licked up his arms. The heat pouring off him was almost unbearable, and Gray grit his teeth against the pain as he pushed forward again. "Burn it to ash."

"No, you don't," Gray insisted between coughs. His lungs burned and every breath was a wheezing gasp that nearly dropped him to his knees. "It's over, you got him. We got him. You can stop now."

"No!" Natsu shouted, and the flames on his arms sparked, turning darker until they were nearly black. "Ashes. All of it, has to…"

Before Natsu could continue, Gray dashed forward, grabbing both Natsu's wrists and pulling him close. It was like grabbing hot coals, burning into his flesh, and Gray bit down on the scream bubbling in his throat.

"Stop," Gray begged, gagging on the scent of scorched flesh. It hurt more than anything he'd felt before – a sharp, searing pain that ripped through his arms and down his bare chest, tearing away pieces of him and leaving nothing behind but blackened skin. "Stop, Natsu, please. It's me. C'mon, look at me."

Natsu's arms shook beneath Gray's hands, and Gray could see a flicker of recognition in the dark of Natsu's eyes.

"There you go," Gray gasped through the smoke. "C'mon, love. Come back to me."

Slowly, Gray let go of one of Natsu's wrists and brought his hand up to Natsu's face. His blistered fingers trailed over the dragon scales as he cupped Natsu's cheek, then leaned in and pressed their foreheads together.

If Gray was going to die, he would happily burn for Natsu.

"I love you," Gray said, then pulled Natsu closer and kissed him.


	2. Chapter 2

As soon as their lips touched, Natsu detonated.

Fire coursed along every inch of his skin, burning so bright that it pierced through Gray's closed eyelids. It filled the space between them; a tension building above their heads that stretched and crackled until it burst out in a spiral of flame. The blaze exploded through the ruins of the city – brilliant tornadoes of orange light that licked at the remains of charred buildings and glinted off shattered glass.

Gray braced himself for the pain, but none came – instead he felt nothing but a tingling warmth that surrounded them both.

As quickly as the flames had appeared, they dissolved, leaving nothing but tiny cinders that drifted around them like fiery snowflakes. Natsu kissed Gray like it was the only thing keeping him alive, like if they stopped breathing against each other, Natsu would stop existing and dissolve into sparks.

"I'm here," Gray murmured, tightening his fingers in Natsu's hair and moving his other hand to wrap around Natsu's waist. "I've got you."

Natsu's breath stuttered and he pulled back from Gray, staring down at his hands. The dark flames had receded, leaving nothing but reddish marks like healed burns.

Natsu looked up at Gray with unfocused eyes, then slumped forward, head hitting Gray's shoulder as they both sunk to their knees.

Gray gasped as the pain returned full force, blistering across his skin until he was dizzy and choking on smoke and ash. He clutched Natsu tightly, fingers digging into Natsu's shoulders as he let out a pained cry from between gritted teeth.

Natsu was heavy against him, and panic joined the pain as Gray brought trembling fingers to Natsu's neck. A pulse fluttered there, weak and erratic.

Gray closed his eyes, exhaling sharply as the devil slayer marks on his skin surfaced, spreading and winding until they covered half his body. Everywhere they touched felt cool – a gentle relief from the searing pain.

"We're okay," he whispered, tugging at the magic, trying to spread it further across his blistered skin. His arms shook with the effort of holding up Natsu, but Gray refused to let go. "It's gonna be okay," he said again, pressing a kiss to Natsu's hair.

When Gray finally collapsed, there was nothing left of the city but ash.

* * *

Gray woke up in and unfamiliar room with Natsu curled around him. He blinked a few times, trying to clear his blurry vision as he looked around. Two beds, a washbasin, a window spilling in bright sunlight, luggage stacked along the wall. Gray felt unreal; a hazy film filling his head where memories should be.

Gray looked back down at the messy head of pink hair that rested on his chest.

"Hey," Gray said, nudging Natsu and wincing as his voice scraped along the inside of his throat. Natsu's eyes flew open and the confused, sleepy expression on his face was quickly replaced with one of relief.

"Gray," Natsu breathed, sitting up and reaching out to touch Gray's cheek. Natsu's face was a blotchy mess, tangled hair falling into red-rimmed eyes. "You're okay."

Gray tipped his head into Natsu's palm, sighing at the gentle touch. Natsu brushed his fingers through Gray's hair, then leaned in and kissed his forehead.

"What happened?" Gray asked, pushing himself up on one elbow. A searing pain rushed up the left side of Gray's body and he hissed in pain, clenching his teeth.

"Careful," Natsu said gently, putting his hand on Gray's back and helping him sit up. As Natsu stacked several pillows behind him, Gray's gaze dropped to the bandages that covered the left half of his body. A singed patch of skin peeked out from the edge of one of the wrappings – red and pink blisters against Gray's dark skin.

Smoke and flames filled Gray's mind and he squeezed his eyes shut, bringing his hand up to his head. "What…" Gray's throat burned, and he started to cough, doubling over and crying out in pain as the motion pulled at his bandages.

A cup of water appeared in his hand and Gray took it, gulping it down gratefully. Then he sighed and tipped his head back against the headboard. Natsu's hand withdrew from where it had been combing through Gray's hair.

"I'm sorry," Natsu whispered, looking down at his hands. Gray followed his gaze – Natsu's skin was unblemished, no sign of the destruction that had exploded from him.

"You… the fire." Gray said slowly. "You ate those weird flames, and…"

"And I hurt you," Natsu said, voice thick with shame. "That… it's my fault." He gestured to the bandages on Gray's arm, then rubbed at his face. "Fuck, I'm so sorry."

"Are you okay?" Gray asked, reaching out and taking Natsu's hand. Natsu tried to pull away from him, but Gray didn't let go.

"You're the one that's hurt," Natsu whispered.

"I'm fine," Gray insisted.

"You're _not _fine!" Natsu's cheeks were pink, eyes wet with tears, and he tried to pull away from Gray again.

Gray shook his head and grabbed both Natsu's wrists, ignoring the pain and pulling Natsu close again. "Don't push me away," Gray murmured, pressing their foreheads together. "Yeah, it hurts like hell, but I'm okay because _you're_ okay."

"I hate seeing you hurt," Natsu whispered. "I don't… I can't remember." He looked up again, pulling one wrist out of Gray's grasp and running his fingers lightly up Gray's bandaged arm. "I did this."

"I let you," Gray said. Natsu's brow furrowed in confusion, and Gray sighed. "You think I couldn't have kicked your ass if I wanted to?" He squeezed Natsu's hand and the black marks began to crawl up his arm, soothing the ache of the burns as they twisted around his bicep and up to his cheek.

"Then… why didn't you?" Natsu asked, voice breaking. "You could have…"

"What would that have done?" Gray asked, tugging on Natsu's hand until Natsu curled back up against his uninjured side, head resting under Gray's chin. "I knew I could bring you back."

A silence descended over them and Gray breathed deeply, pressing his face into Natsu's hair. He still smelled like ash, like smoke and flame, but underneath it was something warm and familiar that felt like home.

"I'm dangerous," Natsu said eventually. His voice was soft and small as he traced the black marks on Gray's chest with his fingertips.

"We both are," Gray said softly, placing one of his hands over Natsu's heart. "I know that scares you, but you're not alone."

Natsu covered Gray's hand with his own, swallowing hard as he moved his gaze over to the door. "They're scared of me, now," he said, and it was both a statement and a question.

"Maybe," Gray admitted, holding Natsu tightly against him. "But I'm not." He kissed Natsu's head. "And I never will be."


	3. Chapter 3

The ruined city sprawled before them, a wasteland of blackened rubble, lain untouched over the week since the battle. Shattered glass and splinters of wood lay buried beneath piles of ash that the wind picked, shifting it back and forth across the scorched earth.

Natsu didn't speak as they walked through the wreckage, just trailed his fingers over the ruins until they came to the spot where he'd detonated.

"How the hell did you survive?" he whispered.

Natsu stared at the ground, crouching down and running his fingers over the dark marks along the earth. Charred lines exploded out from the point where they stood, stretching like broken fingers clawing their way across the rubble.

"You're giving yourself too much credit," Gray said wryly, leaning back against a blackened pillar. Natsu glared at him, teeth worrying his lower lip. "I'm not afraid of you."

"You should be!" Natsu said, standing up and gesturing around them. "I destroyed… this entire city is _gone _because of me."

"That's bullshit and you know it," Gray growled, shoving Natsu's shoulder and pointing behind him. Splintered bits of wood stretched from the ground, nothing but a skeleton of a building huddled against the grey sky. "I did that."

"Yeah, but—"

Natsu's words were interrupted by an enormous wall of ice bursting out of the ground behind him, tearing through the burned buildings and reaching up into sharp, scintillating peaks. The impromptu mountain crackled and snapped as it grew, the edges taking on a blackish-purple sheen, bruised and deadly.

"See?" Gray's voice was rough, and Natsu watched, entranced, as the black marks of his magic spiraled across his skin – an eerie echo of the whitish scars that Natsu's flames had left behind. "You're not the only one who can destroy things," Gray said. Then he closed his hand and the ice wall shattered into a billion tiny, razor-sharp pieces.

Natsu cursed, hands coming up instinctively to block the shards with flame that melted them before they could touch his skin. "What the hell?" he asked, turning to glare at Gray again.

"You're fine," Gray said, rolling his eyes. Natsu opened his mouth to protest, but Gray shook his head. He turned his hand toward Natsu and the melted ice re-solidified into sharp crystals that hovered in mid-air, the same eerie, bruised color as before.

"You can—"

The ice crystals all exploded simultaneously and Natsu swore again, dropping into a defensive stance as he blasted them all away. Before he could retaliate, the ground under his feet began to shake, and he stumbled back as sharp, deadly spears of ice exploded from the earth, narrowly missing him.

"Stop it!" he shouted, melting the ice as quickly as Gray could form it. He threaded his way backward through the spikes, scowling at the smirk on Gray's face. "What are you doing?"

"Are you afraid of me?" Gray asked, voice low.

The question was pointed, but the way Gray said it brought up some entirely different feelings that had nothing to do with Natsu's fear, and everything to do with wanting Gray to take him against the nearest surface.

"No," Natsu said, still backing away from Gray's attacks. They were rapid, now – a barrage of frozen splinters that pinned Natsu back against a wall that suddenly appeared behind him.

"You should be," Gray said, bringing both hands into his chest and then thrusting them forward. The marks moved on his arms like a living thing, creeping up until one of his eyes was as bright as winter sky. More ice appeared around Natsu, cracking the ground beneath him and slicing through his clothes.

A stinging pain on Natsu's forearm shocked him out of his stupor. He stared down at the blood beading on the surface of his skin where one of the shards had nicked him. It wasn't deep – barely a scratch – but the sensation left him winded.

Then cold bit against his skin, shackles of ice wrapping around his biceps, wrists, thighs, ankles. Thin, piercing shocks of pain spread out from everywhere that the ice touched him, digging into his skin and pinning him to the wall.

"You gonna surrender?"

Natsu jumped as Gray appeared in front of him, one hand flat on the ice beside Natsu's head, the other grasping his scarf and tugging him forward. Gray's face was so close to his – the air started to crystallize, their breath steaming between them.

"I could kick your ass," Natsu murmured, voice trembling as a fire grew in his chest, spreading outward until he could feel it on his fingertips. Gray shook his head, gazing at Natsu intently, pinning him with an unnaturally multicolored gaze. The darkness spread across Gray's cheek and down his neck, and the ice gripped Natsu harder.

"Do it," Gray challenged, tightening his grip on Natsu's scarf and pulling him closer. He leaned in, brushing his lips over Natsu's cheek as he slid his fingers up into Natsu's hair. "If you're so dangerous… prove it."

The last words were whispered as Gray's teeth grazed Natsu's earlobe, and a thrill coursed through Natsu's body, vibrating everywhere that Gray pressed against him. Natsu let out a stuttered, noisy breath that hung heavy between them, then met Gray's gaze and leaned in to kiss him.

"That's better," Gray breathed, biting down on Natsu's lip and pulling hard on his hair. Natsu gasped, tongue tracing the shape of Gray's mouth as he ground his hips forward and whispered Gray's name. "There you go," Gray murmured, lips moving down to Natsu's jaw, across his throat, teeth sinking into sensitive skin. "Say my name just like that."

"Gray," Natsu moaned as Gray's ice tightened around him again, and Gray's hand trailed down his stomach, then over his cock. Natsu thrust up into his hand, whimpering at the harsh touch.

"I'm gonna tear you apart," Gray growled, deft fingers tugging at the laces on Natsu's pants. His voice softened for a minute as he whispered a gentle, "okay?" in Natsu's ear.

"Yes, fuck," Natsu gasped as Gray tore his pants open, dragging them down to his thighs and then wrapping a cold hand around his cock. "Please."

"I've got you," Gray promised, covering Natsu's body with his own, an oath that if either of them becomes a demon, the other will bring them back.

* * *

Afterward, they sat against the wall, sprawled in the ruins of their devastation. Natsu ached and was covered in ash, and he felt alive and content and safe in Gray's arms.

Safe from himself and everything else.

"Maybe there's a little bit of monster in both of us," Gray murmured, pulling Natsu back against his chest and kissing his temple. "But I love you. All of you, even the parts that scare you, because those are the same parts that make you strong and brave."

The black marks flickered across Gray's palm and down his fingertips, and he curled his hand around Natsu's.

"You're not scared of me?" Natsu asked. Gray shook his head, wrapping his arms around Natsu.

"No," Gray said, leaning in and kissing Natsu's neck as he rubbed his thumbs over the backs of Natsu's hands. "The only thing that scares me is losing you."

"What if I lose myself?" Natsu whispered.

Gray tipped Natsu's head back, pulling him in and pressing a harsh, desperate kiss to Natsu's lips.

"That's easy," Gray whispered, running his tongue over Natsu's sharp teeth. "I'll bring you back." Natsu moaned quietly, fingers digging into Gray's forearms as he kissed back, hard. "And if I can't bring you back," Gray added, "then we'll lose ourselves together."


End file.
